The preacher in Ecclesiastes examined the nature of man. He concluded that man, in part, is like the beasts. He is made of dust and returns to the dust of the earth (Ecclesiastes 3:18-21). But the preacher also concluded that another part of man is like God. Man is spirit, and the spirit returns to God who gave it (Ecclesiastes 12:5-7).
The Bible provides other examples of this principle that man has two natures, fleshly and spiritual...
In the Bible, the spiritual nature of man is referred to by various terms which are interchangeable as you can see by comparing all the scriptures cited in this lesson.
Some say that man is "a triune being" which means that man has three natures, namely body, soul, and spirit. The difference between the body and the spirit is clear. But the difference between the soul and spirit is vague, and perhaps we ought to regard it as "a distinction without a difference".
When the Bible uses the term "flesh and blood", it is not referring to two different natures of man, but one nature, that is the "earthy" nature (1Corinthians 15:48-50).
In the same way, when the Bible uses the term "soul and spirit", it is not referring to two different natures of man, but one nature, the spiritual. For example, when Mary said, "My soul exalts the Lord and my spirit has rejoiced in God my Saviour", she was not saying two different things, but saying the same thing two ways (Luke 1:46-47).
A couple of "proof texts" (1Thessalonians 5:23, Hebrews 4:12) are used to support the idea of man as a triune being, and these are worth examining.
In the Hebrews passage, the distinction between "soul and spirit" is no more significant than the other distinctions in the verse, namely "joints and marrow", or "thoughts and intentions".
In the Thessalonian passage, there is an emphasis and enthusiasm for the idea of the "complete" and "entire" sanctification and preservation of the person. Some redundancy of expression is to be expected here for emphasis.
Arguments based on these "proof texts" for a triune nature, are thus extremely weak, and consist of "reading in" to the passages something that really isn't there.
Some say man is wholly physical. They say spirit and soul mean the breath of life (Genesis 2:7).
A few places can be found where, in the same sentence, the same Hebrew or Greek word is used in one case "spirit" and in another case for "wind" or "breath" (eg Genesis 2:7, John 3:8, Acts 2:2-4).
Again, the same word for "soul" can mean "life" in the earthly sense. (eg Matthew 6:25, Matthew 20:28).
All this proves, however, is that one word may have more than one meaning —a fact we are all aware of. A humourous example of the folly of the argument that "spirit" means "breath", is that it might suggest the apostles, in casting out "evil spirits" were curing bad breath! (Acts 19:11-12).
In this lesson we have looked at doctrines of the nature of man, in which some teach man has one nature, others say he has two natures, and yet others say he has three natures. Our examination of the scriptures has shown us that the doctrine that man has two natures (flesh and spirit) is the correct one.